The Lunar Dragon
by Jayswing103
Summary: After destroying Eclipse and stopping the dragon invasion Natsu finds himself in Equestria 1000 years before the return of Nightmare Moon and decides to pledge his life to Luna to pay her back for saving him.
1. Chapter 1

Natsu let out a pained groan as he traveled along through the dark forest. He had a large gash across his chest from when a piece of the Eclipse portal had hit him, and while it wasn't life threatening it still hurt. "Jeez, I wish Happy were here." he complained, allowing himself to sit down and slump against a tree, "Maybe I'll just... rest... a bit." With that he was out like a light.

 _Natsu, Lucy, and Happy were gathered together in front of Eclipse, joined by both Arcadios and the princess. "Alright, let's bust that thing up!" Natsu exclaimed._

 _"But how?" Arcadios questioned, "Eclipse is made of magnanium alloy which is highly resistant to magic."_

 _"Still we have to try." Lucy said, "If we can't destroy it then everyone is in danger." It was then that Natsu realized what he had to do if he wanted to protect everyone._

 _"Get back." he told them._

 _"Wait, Natsu!" Lucy called out, "What are you planning to do?"_

 _"Isn't it obvious?" he asked, "I'm going to destroy that thing from the inside!"_

 _"But if you do that-"_

 _"Don't worry, I'll be fine. After all I'm a Fairy Tail Wizard." Lucy stared at him for a moment before nodding her head._

 _"Yeah! I believe in you Natsu."_

 _"I know. Happy get Lucy outta here."_

 _"Aye!" with that Happy took hold of Lucy and flew off._

 _"You better come back alive!" Natsu paused heading towards the portal before raising his arm and sticking out his index finger and his thumb. With that he took off again before jumping into Eclipse._

* * *

"...do with it sis?"

"...leave it."

"But we can't just leave it, it's injured."

"It might be dangerous. You can feel how much magic it has, what if it decides to turn on us?"

"Just because it's different does not mean it is a threat, sister, and I will not brook any more objections."

"Very well Luna, but on your own head be it."

* * *

"Ugh." Natsu let out a groan as he regained consciousness.

"Oh, you are awake. Do not worry I'll take care of you."

"Thanks." he managed to mutter.

"Ah, so you can talk. Well then might I ask what your name is?"

"Natsu."

"Well then, it is a pleasure to meet you Natsu. I am Princess Luna, diarch of Equestria. May I inquire as to how you acquired such wounds?"

"Dragons." was all Natsu managed to say before he felt his conscious fading again.

Natsu let out a loud yawn upon awakening and did a few stretches before he opened his eyes and took note of his surroundings. He had been moved, likely by the person he had talked to earlier, into what seemed to be a rather luxurious room. The room itself was made from a pure white marble and was filled with various expensive looking furniture. Even the bed he found himself on was something he'd imagine a rich person to have.

Upon looking down and examining his own body he found that he had been wrapped in bandages and his wounds had been treated. It was then that his enhanced hearing picked up a sort of clopping sound heading in the direction of his room. After a few moments the sound stopped right outside of his door and he watched as the handle was turned, the door pushing inwards to reveal a dark blue horse with a horn and a pair of wings. Her hair also appeared to be stuck in a phantasmal wind.

"Ah, I am glad to see you have awakened." she spoke, "You may not remember, but I am Princess Luna. I'm the one who brought you here and healed you."

"Oh, you're the person I talked to earlier," Natsu said, "Thanks for helping me out."

"Twas nothing, it is my duty as a princess to help those in need." she told him, "By the way, may I ask what species you are? I have not met anything quite like you before."

"Sure, I'm a human. What are you?" he questioned.

"I am a pony. Or more specifically an alicorn." she answered, "Excuse me Mr. Natsu, but-"

"Just call me Natsu." he interrupted.

"Very well then Natsu," she agreed, "Earlier you said you acquired these wounds from dragons. Would you care to elaborate?"

"Huh? Oh, these aren't actually from dragons, I mean there were dragons involved but it's kinda hard to explain."

"Do not worry, I have plenty of time to listen."

"Right, well it all started when we entered this tournament."

* * *

"And that's how I ended up here." Natsu had just finished explaining the events that had brought him here to the Princess and she looked at him with interest.

"I see," she said, "That is a very interesting tale indeed. So what is it that you intend to do now?"

"Actually I was hoping that you could tell me."

"What?"

"Well you did help me after all, and a Fairy Tail wizard always pays his debts!"

"Very well then, I suggest that you get some more rest right now. If you don't mind though I would like to see a display of this 'dragon slayer' magic later."

"Got it!" he exclaimed, giving her a large smile. Luna couldn't help it as a smile of her own wormed it's way onto her face.

"I look forward to it."

* * *

It was the day after Luna had found him and brought him in and Natsu sat waiting for Luna to come and get him. He had stayed inside the room the whole time he had been here so he was excited to be able to get out and stretch. It wasn't too long before he recognized the familiar clopping of Luna trotting along the hallway. A few moments later the door opened, allowing Luna to trot in.

"Greetings Natsu." Luna greeted as she entered the room.

"Hey." Natsu greeted back.

"Are you ready to leave?" she questioned.

"Yeah!"

"Very well then, follow me. There's a field not too far from the palace that we can use. We shouldn't disturb anypony there."

"Got it!"

* * *

It had taken the pair a little while, but eventually they managed to make their way out of the castle and over into the open field that lay next to it. Once they were a good distance away they stopped. "I believe that this will suffice." Luna said.

"Right, what do you wanna see first?"

"How about you start by showing me how you produce flames?"

"Well there's not really much to it," he admitted, "I just," With that he held his hand out and a flame popped into existence.

"That is indeed very interesting magic. Those are no ordinary flames either, they are laden with powerful magic, like the flames of a dragon. Such magic truly does deserve the title of 'dragon slayer'."

"Anything else you wanna see?"

"Ah, yes, I understand that you use these flames to fight in a multitude of ways, but I believe that I would like to see this 'breath' attack next."

"Sure!" Having said that Natsu took in a deep breath before tilting his head up. "Roar of the fire dragon!" With that Natsu unleashed a large torrent of flames from his mouth which flew a good ways up into the air before dissipating. Eventually Natsu ran out of breath and the flames died down as he stopped. Luna was staring at him in awe as she spoke, "To be able to produce flames of such strength with such ease. You indeed garner much power which is why I believe-"

"Luna!" Both Natsu and Luna turned their heads in the direction of the shout to find a white winged unicorn a little taller than Luna herself gliding down towards them. Once she touched down she raced towards them, coming to a halt in front of Luna. She spared a moment to toss a glare Natsu's way before focusing on Luna.

"Luna, I saw the fire. What happened?! Are we under attack from a dragon?!"

"Calm down Sister," Luna tried to reassure her, "Twas no dragon, rather it was merely Natsu giving me a demonstration of his magic."

Celestia's eyes widened upon hearing this. "What? What kind of magic could have possibly created fire like that?"

"It's called dragon slayer magic." Natsu said, lighting a small fire in his hand.

Without warning Celestia turned on him, her horn alight, and shot him with a ball of magic. The force of the blast sent him flying away into a tree with enough force to topple it.

"SISTER!" Luna quickly rounded on her, "WHAT IN THE NAME OF TARTARUS POSSESSED YOU TO DO THAT?!"

"You heard him yourself Luna! He's a dragon slayer!"

"You do not understand sister! It is not named as such because it is used to slay dragons, rather that it is taught by the dragons themselves!"

"And why should you believe him?!"

" **And pray tell, what has he done to garner our distrust?!** " Luna questioned, her face beginning to turn beet red in anger.

Celestia was about to respond, but a loud groan caught their attention.

"We will finish this conversation later _dear_ sister," Luna said, glaring daggers at Celestia, "For now I must tend to Natsu's wounds, which _you_ created." With that she flew over to the fallen tree where Natsu lay. As his eyes fluttered back open they landed on Luna and gleamed with recognition.

"What happened?" he questioned.

"I'm sorry Natsu," Luna apologized, "My sister overreacted when she heard about your magic and took rash action. I hope you are not too harmed."

"Nah, it's fine," Natsu waved her off, "I've gotten a lot worse from my fights with Erza."

Upon hearing this Luna let out a sigh of relief, glad that Natsu was safe. "Well, while I would very much like to see more of your magic I believe that it is best that we do such at a later time. For now I believe that you should get some rest, I will escort you back to your room."

"Thank's Luna!"

"Think nothing of it," Luna told him, blushing, "You are great company, plus you enjoy my nights as well."

"Your nights?" Natsu questioned, confused.

"Ah, that's right, I've been so fascinated by your world that I have yet to tell you about mine. Very well I shall remedy that. Come, I believe that it is time I taught you about my own world. The world of Equestria."


	2. Chapter 2

"Woah!" Natsu exclaimed, "You mean you raise the sun and moon? That's awesome!"

Luna blushed at the praise.

"Not really, a team of unicorns used to do the same thing before me and my sister came to rule."

"Yeah, but you can do it by yourself! Just cause other people can do it too doesn't mean you're any less amazing."

Luna's face flushed an even deeper red from the continued praise.

"Thanks Natsu. Truth is I don't often hear words of praise, most of that falls upon the ears of my sister so it's nice to appreciated for once."

Natsu simply smiled at her, but for some reason she felt her heartbeat fasten. She quickly coughed in her hoof to distract herself and gain the attention of the being next to her.

"As I was going to suggest earlier, before my sister so rudely interrupted, was that you become my official Lunar Guardian."

"Lunar Guardian? What's that?"

"A Lunar Guardian or a Solar Guardian are a form of knights that are hoof-picked by either me or Celestia. They are the highest within the chain of command and report directly to us, they are also tasked with protecting the life of their princess, even at the cost of their own. It is one of the greatest honors I can bestow upon someone, but it is also one of the most dangerous, should you decline I won't hold it against you."

"Sure."

Luna was taken aback by Natsu's lack of hesitation.

"Are you sure? You do not wish for any time with which to ponder your decision?"

"Nope. Like I said I'm a Fairy Tail wizard, and Fairy Tail wizards always repay their debts no matter what!"

"You are very courageous, I believe you will make for an excellent Lunar Guardian."

"Thanks! So what do I gotta do?"

"Your responsibilities will mainly consist of following me around and protecting me from any potential danger I may find myself in. However should times of emergency come you will be allowed to act of your own free accord in whatever manner you find appropriate. You will also have the power to mobilize the rest of our guard force should a major conflict arrive."

"I don't really get most of what you said, but I just have to protect you right?"

"Essentially. We can go over the finer details at a later date. For know please kneel down."

Natsu did as he was told and got down on one knee with his head lowered. Luna moved up to him and lowered her horn onto his right shoulder then lowered it onto his left.

"By the power bestowed upon me as diarch of Equestria I hereby name thee, Natsu Dragneel, as an official Lunar Guardian. When the time comes you shall be expected to protect me, and Equestria, even if it should be at the cost of your life. Rise."

Natsu stood up straight as he was told.

"You are now a Lunar Guardian. From now on, wherever I go you will follow. Should I be placed in danger you will protect me from it. In return you will be fed and sheltered. And I shall personally teach you everything you need to know about Equestria and it's inhabitants."

"Cool." Natsu said, giving her a grin and a thumbs up. It was at that moment Luna's stomach let out a particularly loud growl which made her flush a beet red.

"Ah, it appears that in all this excitement that I have forgotten to eat. I'm sure that you're hungry too Natsu, thankfully dinner should be served soon. Come, let us go partake in the fine cuisines that our chefs have prepared for us today."

"That sounds good to me!"

* * *

As the two made their way through the ornate halls of the castle Natsu took a little time to observe his surroundings. Having been within the hospital ward for the duration of his stay hadn't afforded him much time to look around. The castle itself seemed to be crafted from stone blocks, and the decorations were fairly minimalist with only a couple of busts or tapestries here or there.

Every now and then there would be what seemed to be a guard, or a maid, wandering the halls, but compared to the usual liveliness of the Fairy Tail guild hall it felt kind of empty. Thankfully Luna took it upon herself to fill the silence by humming a nice little tune which reminded him of his friends.

When she finished he found a warm smile had wormed its way onto both of their faces.

"Where'd you learn that?" he questioned.

"Tis a song that our mother used to sing to us before... before she passed away."

"It's beautiful."

"I am glad you see it as such. I often use it in times of hardships to remind myself that all is not lost."

The two fell back into a comfortable silence until they reached the large set of arching doors that led to the dining hall. Using her magic Luna pushed the doors inwards to reveal the elongated room decorated with several stained glass windows and canvases. Taking up most of the room was a large dining table with approximately three dozen seats on both sides with two larger chairs placed at the two ends of the table.

Already seated at the far end of the table was Celestia who seemed a mix between surprise and annoyance.

"Sister you are late. And why, pray tell, is _he_ here?"

"Because, sister, I have an announcement to make." Luna said, sitting in the other end seat, motioning for Natsu to take the place beside her.

"And what might that be?" Celestia questioned.

"I have enlisted Natsu here as my official Lunar Guardian."

There was a loud _thud_ and the table shook as Celestia slammed her hooves down on it.

"Absolutely not!" she exclaimed, "I may have tolerated you taking this thing in, but I won't stand by and watch you give it control over our armies!"

"And what, pray tell, will you do about it?" Luna asked, "As I recall we are equals, you hold no sway over my decisions, nor can you veto them."

"Sister, I implore you, please re-think this!"

"I have made up my mind Sister, and my decision is final."

" _Oh my. What's this? A quarrel between sisters? How unbecoming of princesses._ "

" ** _Discord_**." hissed the two sisters in unison.

"I thought the Elements of Harmony sealed you away." Celestia growled.

" _Please, do you really think that I wouldn't have some backup plan in place? You forget who you're talking to, I'm Discord the master of chaos and manipulation. The Elements of Harmony could never hold me for too long._ "

"Show yourself foul beast!" Luna exclaimed.

" _Well, since you asked so nicely._ "

The sound of a snap could be heard and a strange, twisted beast appeared over the middle of the table.

" _Fire Dragon's Iron Fist!_ "

Natsu suddenly appeared in front of the creature, his fist covered in fire before he slammed it into his face, sending him flying through the castle wall.

"I don't really get what's going on but he's a bad guy right? I'll take care of him."

Without waiting for an answer Natsu leapt out of the hole after him. Discord was laying on the ground rubbing his jaw.

"Now that actually hurt. I'm amazed, just what exactly are you?"

"I'm Natsu, a Fairy Tail wizard!"

"Well Natsu, my name's Discord. It's a pleasure to meet someone who might actually give me a challenge for once."

With that Discord snapped his claws and disappeared before Natsu felt something hit him in the back and send him flying, breaking a few trees in the process. Natsu flipped around in mid-air and landed on his feet, but Discord was nowhere in sight when he another hit from his right side sent him flying again.

Next time he stopped he was prepared for Discord's trick and caught his fist as it came in towards his left side. Suddenly fire blast out of his right elbow, propelling his fist right into Discord's face.

" _Fire Dragon's Flame Elbow!_ "

Discord's body was sent spinning, but Natsu wasn't done yet. As Discord was still flying through the air Natsu jumped up before taking a deep breath and unleashing a torrent of flames from his mouth which connected with Discord and slammed him into the ground.

" _Roar of the Fire Dragon!_ "

Natsu landed and waited for the dust to clear from the crater, but when it did Discord was nowhere to be found. Suddenly he felt claws raking across his back, injuring him and sending him stumbling forwards right into Discord's punch which sent him stumbling backwards. Natsu looked up at Discord and noticed that his fur was singed in some placed and that he was bleeding.

"You've managed to make me angry, boy. Don't expect me to hold back any more."

"Then neither will I." Natsu said.

Suddenly Natsu's arm became coated in fire, but it didn't stop there, lightning started dancing around it too. With that he rushed Discord who disappeared, but Natsu turned around and caught Discord in the face as he appeared behind him.

" _Lightning Fire Dragon's Firing Hammer!_ "

Discord was sent flying by a large burst of fire and lightning that cut an enormous swathe through the trees.

"Natsu!"

Natsu turned towards the voice and saw Luna and Celestia floating down with what looked like six gems floating in their grasp.

"Natsu, what happened? Did you beat him?"

"I think so," he said, "But I'm not really sure yet, he's pretty tough."

"Don't worry, if you weakened him then we should be able to use the Elements of Harmony to turn him back to stone. He shouldn't be able to escape again."

"I won't let that happen. The Elements of Harmony need both of you to work right? So if I get rid of one of you then I should be fine."

Discord materialized behind Luna, his body battered and broken but with a dangerous glint in his eye. Within his lion's paw he held a sword that was pitch black.

"Obsidian, the only material able to kill immortals."

With that he brought the blade down towards Luna and she closed her eyes waiting for the inevitable, but it never came. She opened her eyes and gasped in horror when she saw that Natsu was standing in front of her and had taken the blow, a large gash running diagonally across his chest was bleeding profusely.

" _ **NATSU!**_ "

Discord started to cackle and then began to laugh uproariously as Natsu's body tumbled backwards. Rushing forwards, tears streaming down her face, Luna caught him and laid him down gently.

" _Natsu, please._ "

"This is hilarious! It's just like a fairy tale where the knight in shining armor lays down his live to save the fair princess." Discord's grin grew malevolent, "Except in this fairy tale there's no happy ending."

" ** _Discord!_** " Luna screamed, enraged.

Luna's horn began to glow a dark, ominous purple and her eyes became tinted green.

"Oh," Discord said, sounding more amused than surprised, "Turning to dark magic now are we? Are you sure that's wise?"

"Sister please!" Celestia pleaded, "Think about what you're doing. Once you use black magic you will be trotting down a path you cannot return from!"

" _ **I don't care. You hurt the ones I care about Discord, and for that, no matter the cost, I will see you dead!**_ "

Luna's horn glowed an even deeper purple as she prepared to strike out at Discord when she was stopped by something pressing against her cheek. She looked down and saw that Natsu had placed his hand on her, his eyes filled with sorrow.

"Luna, don't."

Those two words instantly vanquished any anger within her, only for it to be replaced with sorrow.

"I'm so sorry Natsu. I couldn't protect you, I couldn't do anything. You're like this because of me."

Natsu let out a weak chuckle.

"Don't you remember. I'm the one who promised to protect you, and a Fairy Tail wizard always keeps his promise."

Luna hugged him tight, not caring that blood was staining her fur crimson.

"You did. I'm sorry. Please is there anything I can do?"

"Yeah, I'd like a snack, do you have any fire?"

"Fire? I thought you were hungry."

Natsu chuckled.

"I am. As a fire dragon slayer I can eat fire."

Luna chuckled as well.

"You certainly are strange, however if it is fire that you wish, it is fire you shall get."

Luna's horn glowed a calming blue hue as her magic swirled around before gathering together at one point. The fire she had created was not like any normal fire, no, instead it was pitch black with dozens of small lights twinkling inside it, as if it were the manifestation of the night sky itself.

"Here, eat this."

Natsu opened his mouth and inhaled, the flames being sucked in as he ate them.

As he absorbed the flames Luna noticed startling changes starting to take place. The gash on his chest had suddenly stopped bleeding, and his face appeared to have scales on it now. Not only that, but she could sense the magic power inside him rising to new heights. Without any hesitation he stood up and wiped his mouth.

"Thanks for the meal."

Luna could only stare in amazement as Natsu suddenly became wreathed in flames similar to the ones he had just eaten.

"No way. What... What are you?" Discord asked, actually appearing frightened for the first time in his life.

"I already told you, I'm a Fairy Tail wizard!" Natsu exclaimed, using his left thumb to point at the mark on his shoulder, "I made a promise to protect this place, and a Fairy Tail wizard never breaks his promise!"

With that Natsu once again launched himself at Discord before peppering him with a barrage of punches.

" ** _Dragon Slayer Secret Art Crimson Lotus: Lunar Fire Dragon's Fist!_**

Natsu then leapt up, fire in both his hands which he brought together into a giant fireball above his head.

" _ **Lunar Fire Dragon's Brilliant Flame!**_ "

With that he tossed the fireball down at Discord which burst upon touching him, destroying everything around him. As Natsu landed back down by the princesses they were both staring wide-eyed at him. Luna in amazement, and Celestia in fear.

"Natsu that was amazing!" Luna exclaimed as she rushed over to him and jumped up to hug him.

"Heh, thanks. Just doing my job. Now if you don't mind I need some rest."

With that Natsu collapsed which worried Luna until she heard his snoring and let out a sigh of relief.

"Thank you, you deserve it."

"If you are done sister there's something still left to do." Celestia interjected.

Luna got a harsh look on her face as she remembered that Discord was still free.

"Right, let's end this."

Trotting over the two saw Discord laying in a crater, his body completely battered with most of his fur singed. As the two prepared the Elements of Harmony a second time Discord let out a weak chuckle.

"This won't be the last you see of me. Someday I'll break free again, and that time your knight won't be there to protect you."

"I doubt it." Luna said icily as the Elements of Harmony lashed out leaving Discord petrified.

Letting out a sigh of relief Luna was finally able to relax.

"If you don't mind Sister I need to take Natsu to the hospital ward and then I'd like to get some rest.

"Very well Sister, just, be careful."

Luna's eyes hardened.

"Are you still on about that? Even after he saved us? Even after he risked his life to protect me?"

"Luna I-"

"No! I won't hear any more of it! He has already proven he is more than trustworthy! What more does he have to do to gain your acceptance?"

"Luna please."

"Just- Just leave me alone."

With that Luna gripped Natsu with her magic and stormed off, leaving Celestia alone to stare at the sheer destruction that had been wrought by the battle.

" _I hope you're right. For both our sakes._ "


End file.
